We all agree that drinking water should be clean and safe, but not everyone may understand how it’s done. The best method is also the simplest: Protect your source!

The concept of protection is simple: prevent contaminants from reaching the source, which is more cost-effective than removing contamination after the fact. The cities of Auburn and Lewiston can take pride in the fact that Lake Auburn is one of only a handful of surface waters in the U.S. that has pure enough water to get a waiver from the U.S. Environmental Protection Agency from expensive, complex filtration. But clean water doesn’t just happen by itself. Diligent water quality monitoring and an extensive water supply protection program have maintained that filtration waiver since 1991, saving water users tens of millions of dollars in treatment and operation costs.

So how do we protect Lake Auburn? The objective is to keep contaminants out of the water through management of the lake and its watershed, which is why we have rules and regulations. The answer to the common question, “Why can’t I swim in Lake Auburn?” is that any body contact with the water can introduce harmful coliform bacteria, which can jeopardize the filtration waiver and require expensive treatment. Human contact isn’t the only concern; domestic and wild animals, including seagulls that roost on the water, can also introduce harmful coliform bacteria. Small recreational boats are allowed in a certain portion of the lake away from the water intake pipes. In this same “open fishing” area, people can fish from the shoreline.

The watershed must also be managed since the rainwater that falls on it eventually reaches the lake as groundwater, or much less likely, stormwater. Runoff and groundwater can enter the lake directly or through one of the many streams that feed in from the watershed. There’s little or no stormwater runoff from the forest; instead rainwater percolates through the forest soils to become pure groundwater.

But once parking lots, roads and houses are added, stormwater runoff increases and can be polluted by winter salt applications on roadways and parking lots; oil and grease from vehicles; nutrients such as phosphorus and nitrogen from residential and agricultural fertilizer applications; and coliform bacteria from domestic animals.

Nutrients and bacteria are the primary pollutants of concern in surface drinking water. Here’s why: Nutrients such as phosphorus are the food source for algae. Too much phosphorus promotes algal blooms and excessive aquatic plant growth that lead to hard-to-remove taste and odor problems in drinking water. That can turn pristine lakes like Lake Auburn from clear to green, weedy and polluted in a relatively short period of time if left uncontrolled. Some coliform bacteria can cause human illnesses, so levels must be kept to a minimum to keep the filtration waiver.

Surface runoff is not the only source of such contaminants. Septic systems can also threaten lake water quality, with the potential for untreated wastewater entering the lake and contributing both nutrients and coliform bacteria. Keeping houses and septic systems away from the near shoreline and having strong septic system requirements for location, installation, and maintenance are keys to preventing pollution from septic waste.

The Lake Auburn Watershed Protection Commission was formed to protect the watershed and water quality of Lake Auburn. Thanks to the LAWPC and the cities of Auburn and Lewiston, more than 80 percent of the shoreline is owned by the LAWPC, providing a natural buffer that helps protect water quality.

But that doesn’t mean that the LAWPC is ignoring so-called “passive recreation.” In fact, it’s evaluating opportunities to provide more of it to the public, such as cooperative trail systems with local landholders. Passive recreation has little or no impact on the natural environment, and includes walking, bicycling and fishing. It does not include motorized vehicle activity, vegetation removal, or building structures.

To ensure that Lake Auburn remains one of the cleanest lakes in the region, the LAWPC recently contracted with the New England firm Comprehensive Environmental, Inc., which specializes in watershed and water supply management, to update its 1987 Watershed Management Plan. The plan outlines a program to address existing and potential pollution sources in the watershed over the next 10 years to help maintain and improve water quality.

Lake Auburn is an outstanding resource. Let’s keep it that way!

For more information on how you can help protect Lake Auburn’s water quality or to view the Watershed Management Plan, contact Mary Jane Dillingham at 784-6469 or mjdillingham@awsd.org.

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